Cleaning agent with oligoammine activator complexes for peroxide compounds

ABSTRACT

Complexes of the transition metals cobalt, iron, copper, and ruthenium having at least one and preferably at least five ammonia ligands are used to activate peroxygen compounds in aqueous cleaning solutions for hard surfaces. Compositions preferably contain 0.0025% to 0.25 by weight of the activating complex.

This invention relates to the use of certain oligoammine complexes oftransition metals as activators or catalysts for peroxygen compounds,more particularly inorganic peroxygen compounds, for bleaching coloredstains on hard surfaces and to cleaning formulations for hard surfacescontaining such activators or catalysts.

Inorganic peroxygen compounds, more particularly hydrogen peroxide, andsolid peroxygen compounds which dissolve in water with elimination ofhydrogen peroxide, such as sodium perborate and sodium carbonateperhydrate, have long been used as oxidizing agents for disinfecting andbleaching purposes. In dilute solutions, the oxidizing effect of thesesubstances depends to a large extent on the temperature. For example,with H₂O₂ or perborate in alkaline bleaching liquors, sufficiently rapidbleaching of soiled textiles is only achieved at temperatures aboveabout 80° C. At lower temperatures, the oxidizing effect of theinorganic peroxygen compounds can be improved by addition of so-calledbleach activators for which numerous proposals, above all from theclasses of N- or O-acyl compounds, for example polyacylatedalkylenediamines, more particularly tetraacetyl ethylenediamine,acylated glycolurils, more particularly tetraacetyl glycoluril,N-acylated hydantoins, hydrazides, triazoles, hydrotriazines, urazoles,diketopiperazines, sulfuryl amides and cyanurates, also carboxylicanhydrides, more particularly phthalic anhydride, carboxylic acidesters, more particularly sodium nonanoyloxybenzenesulfonate, sodiumisononanoyloxy-benzenesulfonate and acylated sugar derivatives, such aspentaacetyl glucose, can be found in the literature. By adding thesesubstances, the bleaching effect of aqueous peroxide liquors can beincreased to such an extent that substantially the same effects areobtained at temperatures of only 60° C. as are obtained with theperoxide liquor alone at 95° C.

In the search for energy-saving washing and bleaching processes,operating temperatures well below 60° C. and, more particularly, below45° C. down to the temperature of cold water have acquired increasingsignificance in recent years.

At these low temperatures, there is generally a discernible reduction inthe effect of known activator compounds. Accordingly, there has been noshortage of attempts to develop more effective activators for thistemperature range although the results achieved thus far have not beenconvincing. A starting point in this connection is the use of thetransition metal salts and complexes proposed, for example, in Europeanpatent applications EP 392 592, EP 443 651, EP 458 397, EP 544 490 or EP549 271 as so-called bleach catalysts. In their case, the highreactivity of the oxidizing intermediates formed from them and theperoxygen compound is presumably responsible for the risk ofdiscoloration of colored textiles and, in extreme cases, oxidativetextile damage. In European patent application EP 272 030, cobalt(III)complexes with ammonia ligands which may additionally contain othermono-, bi-, tri- and/or tetradentate ligands are described as activatorsfor H₂O₂. European patent application EP 630 964 describes certainmanganese complexes which do not have a pronounced effect in boostingthe bleaching action of peroxygen compounds and which do not decolordyed textile fibers although they are capable of bleaching soil or dyedetached from fibers in wash liquors. German patent application DE 44 16438 describes manganese, copper and cobalt complexes which can carryligands from a number of groups of compounds and which are said to beused as bleaching and oxidation catalysts.

The problem addressed by the present invention was to improve theoxidizing and bleaching effect of inorganic peroxygen compounds at lowtemperatures below 80° C. and, more particularly, in the range fromabout 15° C. to 45° C.

It has now been found that certain transition metal complexes containingat least one ammonia molecule as ligand have a distinctbleach-catalyzing effect on colored stains on hard surfaces.

The present invention relates to the use of complex compoundscorresponding to general formula I:

[Mn(NH₃)_(6−x)(L)_(x)]A_(n)  (I)

where M is a transition metal selected from cobalt, iron, copper andruthenium, L is a ligand selected from the group consisting of water,hydroxide, chlorate, perchlorate, (NO₂)⁻, carbonate, nitrate, acetateand thiocyanate, x is a number of 0 to 5, A is a salt-forming anion andn—which may even be 0—is a number with such a value that the compound offormula (I) has no charge,

as activators for peroxygen compounds, particularly inorganic peroxygencompounds, in aqueous cleaning solutions for hard surfaces, moreparticularly for crockery.

In the present case, an (NO₂)⁻ group is a nitro ligand which is attachedto the transition metal by the nitrogen atom or a nitrito ligand whichis attached to the transition metal by an oxygen atom. The (NO₂)⁻ groupmay also be attached to a transition metal M to form a chelate

It may also bridge two transition metal atoms asymmetrically:

The above-mentioned transition metals in the bleach catalysts to be usedin accordance with the invention are preferably present with oxidationnumbers of +2, +3 or +4. Complexes with transition metal central atomshaving the oxidation number +3 are preferably used. Preferred complexesinclude those with cobalt as central atom.

Besides the ammonia ligands, of which at least 1 and preferably at least5 are present per transition metal central atom, the transition metalcomplexes to be used in accordance with the invention may contain otherinorganic ligands of generally simple structure (L in formula I), moreparticularly mono- or polyvalent anionic ligands, providing at least oneammonia molecule is present as ligand in the complex. Examples of suchother ligands are nitrate, acetate, thiocyanate, chlorate andperchlorate and the halides, such as chloride, bromide, iodide andfluoride. The anionic ligands are intended to provide for chargeequalization between the transition metal central atom and the ligandsystem. Oxo ligands, hydroxo ligands, amido ligands, imido ligands,peroxo ligands and imino ligands may also be present in addition to orinstead of the ligands L. These ligands may also have a bridging effectso that polynuclear complexes are formed. These complexes contain atleast 1 and preferably at least 4 ammonia ligand(s) and preferably atleast 1 (NO₂)⁻ group per transition metal atom. In the case of bridgedbinuclear complexes, the two metal atoms in the complex do not have tobe the same. Binuclear complexes in which the two transition metalcentral atoms have different oxidation numbers may be used.

In the absence of anionic ligands or if the presence of anionic ligandsdoes not lead to charge equalization in the complex, the compounds to beused in accordance with the invention contain anionic counterions (A informula I) which neutralize the cationic complex. These anioniccounterions include in particular nitrate, hydroxide,hexafluorophosphate, sulfate, chlorate, perchlorate, halides, such aschloride, fluoride, iodide and bromide, or the anions of carboxylicacids, such as formate, acetate, benzoate or citrate. These anioniccounterions are present in the compounds of formula I in such a number(n in formula I) that—in terms of size—the sum of the product of theirnumber with their charge and the product of the number of anionicligands (L in formula I) with their charge is exactly as large, but witha negative sign, as the charge of the transition metal central atom (Min formula I).

In cases where L is a bidentate ligand, for example the carbonatoligand, as mentioned above, optionally the (NO₂)⁻ ligand or the nitratoligand, which occupies two bond sites of the transition metal centralatom in a mononuclear complex compound, formula (I) can only analogouslyreproduce the structure of the complex. Complex compounds such as theseare more clearly represented by general formula (II):

[M(NH₃)_(6−x−2y)L_(x)(L²)_(y)]A_(n)  (II)

where M, A, n and x are as defined above, L is a ligand attached via acoordination site and L² is the ligand attached via two coordinationsites and y is a number of 0 to 2, with the proviso that x+2y is at most5.

Preferred bleach catalysts according to the invention include hexamminecobalt(III) chloride, nitropentammine cobalt(III) chloride,nitritopentammine cobalt(III) chloride, nitratopentammine cobalt(III)chloride, chloropentammine cobalt(II) chloride, tetramminecarbonato-cobalt(III) chloride, tetrammine carbonato-cobalt(III)hydrogen carbonate and tetrammine carbonato-cobalt(III) nitrate and also[NH₃)₅Co—O—O—Co(NH₃)₅Cl₄.

A transition metal bleach catalyst such as this is preferably used incleaning solutions for hard surfaces, more particularly for crockery,for bleaching colored stains. The term “bleaching” in this particularcontext applies both to the bleaching of soil, particularly tea, presenton the hard surface and to the bleaching of soil suspended in thedishwashing liquor after detachment from the hard surface.

The present invention also relates to cleaning formulations for hardsurfaces, more particularly dishwashing detergents and, among these,preferably machine dishwashing detergents containing a bleach catalystcorresponding to formula I and to a process for cleaning hard surfaces,more particularly crockery, using this bleach catalyst.

The use according to the invention essentially comprises creatingconditions—in the presence of a hard surface soiled by coloredstains—under which a peroxidic oxidizing agent and the bleach-catalyzingoligoammine complex can react with one another with a view to obtainingproducts with a stronger oxidizing effect. Such conditions prevail inparticular when both reactants meet in an aqueous solution. This can beachieved by separately adding the peroxygen compound and thebleach-catalyzing oligoammine complex to a solution optionallycontaining a detergent. In one particularly advantageous embodiment,however, the process according to the invention is carried out using adetergent for hard surfaces according to the invention which containsthe bleach-catalyzing oligoammine complex and optionally aperoxygen-containing oxidizing agent. The peroxygen compound may even beseparately added to the solution as such or preferably in the form of anaqueous solution or suspension in cases where a peroxide-freeformulation is used.

The conditions can be widely varied according to the applicationenvisaged. Thus, besides purely aqueous solutions, mixtures of water andsuitable organic solvents may serve as the reaction medium. Thequantities of peroxygen compounds used are generally selected so thatthe solutions contain between 10 ppm and 10% of available oxygen andpreferably between 50 and 5000 ppm of available oxygen. The quantity ofbleach-catalyzing oligoammine complex used is also determined by theparticular application envisaged. Depending on the required degree ofactivation, the activator is used in a quantity of 0.00001 mole to 0.025mole and preferably in a quantity of 0.0001 mole to 0.002 mole per moleof peroxygen compound, although quantities above and below these limitsmay be used in special cases.

The present invention also relates to a cleaning formulation for hardsurfaces, more particularly for crockery, which contains 0.001% byweight to 1% by weight and, more preferably, 0.005% by weight to 0.1% byweight of a bleach-catalyzing oligoammine complex corresponding toformula I in addition to typical ingredients compatible with the bleachcatalyst. The bleach catalyst may be adsorbed onto supports and/orencapsulated in shell-forming substances by methods known in principle.

In addition to the bleach catalyst used in accordance with theinvention, the cleaning formulations according to the invention, whichmay be present in the form of—in particular—powder-form or tablet-formsolids, homogeneous solutions or suspensions, may in principle containany known ingredients typically encountered in such formulations. Inparticular, the formulations according to the invention may containbuilders, surfactants, peroxygen compounds, water-miscible organicsolvents, enzymes, sequestering agents, electrolytes, pH regulators andother auxiliaries, such as silver corrosion inhibitors, foam regulators,additional peroxygen activators and dyes and perfumes.

A cleaning formulation for hard surfaces according to the invention mayadditionally contain abrasive constituents, more particularly from thegroup consisting of silica flours, wood flours, plastic flours, chalks,glass microbeads and mixtures thereof. Abrasives are present in theformulations according to the invention in quantities of preferably notmore than 20% by weight and more preferably from 5% by weight to 15% byweight.

The present invention also relates to a machine dishwashing detergentcontaining—based on the detergent as a whole—15% by weight to 60% byweight and preferably 20% by weight to 50% by weight of a water-solublebuilder component and 5% by weight to 25% by weight and preferably 8% byweight to 17% by weight of an oxygen-based bleaching agent,characterized in that it contains a bleach-catalyzing oligoamminecomplex, more particularly in quantities of 0.0025% by weight to 0.25%by weight, preferably 0.005% by weight to 0. 1% and most preferably0.01% by weight to 0.1% by weight. A detergent such as this is inparticular a low-alkalinity detergent, i.e. a detergent of which a 1% byweight solution has a pH value of 8 to 11.5 and preferably 9 to 10.5.

In principle, suitable water-soluble builder components, particularly indetergents of low alkalinity, are any of the builders typically used inmachine dishwashing, for example alkali metal phosphates which may bepresent in the form of their alkaline, neutral or acidic sodium orpotassium salts. Examples include trisodium phosphate, tetrasodiumdiphosphate, disodium dihydrogen phosphate, pentasodium triphosphate,so-called sodium hexametaphosphate, oligomeric trisodium phosphate withdegrees of oligomerization of 5 to 1,000 and, more particularly, 5 to 50and the corresponding potassium salts or mixtures of sodium andpotassium salts. They may be used in quantities of up to about 55% byweight, based on the detergent as a whole. Other possible buildercomponents are, for example, organic polymers of native or syntheticorigin, above all polycarboxylates, which act as co-builders,particularly in hard-water areas. Suitable builder components of thistype are, for example, polyacrylic acids and copolymers of maleicanhydride and acrylic acid and the sodium salts of these polymer acids.Commercially available products are, for example, Sokalan® CP5 and PA 30(BASF). Polymers of native origin suitable as co-builders include, forexample, oxidized starch, as known for example from International patentapplication WO 94/05762, and polyamino acids, such as polyglutamic acidor polyaspartic acid. Other possible builder components are naturallyoccurring hydroxycarboxylic acids, for example mono- anddihydroxysuccinic acid, α-hydroxypropionic acid and gluconic acid.Preferred builder components include the salts of citric acid,particularly sodium citrate. The sodium citrate used may be anhydroustrisodium citrate and—preferably—trisodium citrate dihydrate. Thetrisodium citrate dihydrate may be used in the form of a fine- orcoarse-particle powder. The acids corresponding to the co-builder saltsmentioned may also be present, depending on the pH value ultimatelyestablished in the formulations according to the invention.

Besides hydrogen peroxide, suitable oxygen-based bleaching agents are,above all, alkali metal perborate monohydrate and tetrahydrate and/oralkali metal percarbonate, sodium being the preferred alkali metal.Hydrogen peroxide can also be produced by an enzymatic system, i.e. bythe use of a combination of an oxidase and its substrate. The use ofsodium percarbonate has advantages, particularly in dishwashingdetergents, because it has a particularly favorable effect on thecorrosion behavior of glasses. Accordingly, the oxygen-based bleachingagent is preferably an alkali metal percarbonate, more particularlysodium percarbonate. Known peroxycarboxylic acids, for example dodecanediperacid, or phthalimidopercarboxylic acids, which may optionally besubstituted at the aromatic group, may also be present in addition toor, more particularly, as an alternative to the above-mentionedbleaching agents. Moreover, the addition of small quantities of knownbleach stabilizers, for example phosphonates, borates or metaborates andmetasilicates and magnesium salts, such as magnesium sulfate, can alsobe useful.

Standard transition metal complexes known as bleach activators and/orconventional bleach activators, i.e. compounds which form optionallysubstituted perbenzoic acid and/or peroxocarboxylic acids containing 1to 10 and more particularly 2 to 4 carbon atoms under perhydrolysisconditions, may be used in addition to the bleach-catalyzing oligoamminecomplexes described above. Suitable conventional bleach activators arethe typical bleach activators mentioned at the beginning which containO- and/or N-acyl groups with the number of carbon atoms mentioned and/oroptionally substituted benzoyl groups. Preferred conventional bleachactivators are polyacylated alkylenediamines, more particularlytetraacetyl ethylenediamine (TAED), acylated glycolurils, moreparticularly tetraacetyl glycoluril (TAGU), acylated triazinederivatives, more particularly1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine (DADHT), acylated phenylsulfonates, more particularly nonanoyl orisononanoyloxybenzenesulfonate, acylated polyhydric alcohols, moreparticularly triacetin, ethylene glycol diacetate and2,5-diacetoxy-2,5-dihydrofuran, and acetylated sorbitol and mannitol,acylated sugar derivatives, more particularly pentaacetyl glucose (PAG),pentaacetyl fructose, tetaacetyl xylose and octaacetyl lactose andacetylated, optionally N-alkylated glucamine and gluconolactone. Thecombinations of conventional bleach activators known from German patentapplication DE 44 43 177 may also be used. In one preferred embodimentof formulations according to the invention, 0.5% by weight to 5% byweight of compounds which eliminate peroxocarboxylic acids underperhydrolysis conditions are present in addition to the complexcompounds.

The machine dishwashing detergents according to the invention arepreferably of low alkalinity and contain the usual alkali carriers suchas, for example, alkali metal silicates, alkali metal carbonates and/oralkali metal hydrogen carbonates. The alkali carriers normally usedinclude carbonates, hydrogen carbonates and alkali metal silicates witha molar SiO₂/M₂O ratio (M=alkali metal atom) of 1.5:1 to 2.5:1. Alkalimetal silicates may be present in quantities of up to 30% by weight,based on the detergent as a whole. Highly alkaline metasilicates arepreferably not used at all as alkali carriers. The alkali carrier systempreferably used in the detergents according to the invention is amixture of carbonate and hydrogen carbonate, preferably sodium carbonateand hydrogen carbonate, which is present in a quantity of up to 60% byweight and preferably 10% by weight to 40% by weight. The ratio ofcarbonate used to hydrogen carbonate used varies according to the pHvalue ultimately required although an excess of sodium hydrogencarbonate is normally used so that the ratio by weight of hydrogencarbonate to carbonate is generally 1:1 to 15:1.

Another embodiment of detergents according to the invention ischaracterized by the presence of 20% by weight to 40% by weight ofwater-soluble organic builders, more particularly alkali metal citrate,5% by weight to 15% by weight of alkali metal carbonate and 20% byweight to 40% by weight of alkali metal disilicate.

Surfactants, particularly low-foaming nonionic surfactants, may be addedto the detergents according to the invention to facilitate thedetachment of greasy soils, to act as wetting agents and—optionally—toserve as granulation aids in the production of the detergents. They maybe present in quantities of up to 10% by weight, preferably inquantities of up to 5% by weight and more preferably in quantities of0.5% by weight to 3% by weight. Extremely low-foaming compounds arenormally used, particularly in machine dishwashing detergents. Preferredcompounds of this type include C₁₂₋₁₈ alkyl polyethylene glycolpropylene glycol ethers containing up to 8 ethylene oxide units and upto 8 propylene oxide units in the molecule. However, other knownlow-foaming nonionic surfactants may also be used, including for exampleC₁₂₋₁₈ alkyl polyethylene glycol polybutylene glycol ethers containingup to 8 ethylene oxide units and up to 8 butylene oxide units in themolecule, endpped alkyl polyalkylene glycol mixed ethers and the foamingbut ecologically attractive C₈₋₁₄ alkyl polyglucosides with a degree ofpolymerization of about 1 to 4 (for example APG® 225 and APG® of HenkelKGaA) and/or C₁₂₋₁₄ alkyl polyethylene glycols containing 3 to 8ethylene oxide units in the molecule. Also suitable are surfactants fromthe family of glucamides, for example alkyl-N-methyl glucamides in whichthe alkyl moiety preferably emanates from a C₆₋₁₄ fatty alcohol. It issometimes of advantage to use the described surfactants in the form ofmixtures, for example a mixture of alkyl polyglycoside and fatty alcoholethoxylates or glucamide with alkyl polyglycosides.

Although it is known that transition metal complexes can counteract thecorrosion of silver, the bleach-catalyzing oligoammine complexesaccording to the invention are generally used in quantities which aretoo small to be able to protect silver against corrosion so that silvercorrosion inhibitors may be additionally used in dishwashing detergentsaccording to the invention. Preferred silver corrosion inhibitors areorganic disulfides, dihydric phenols, trihydric phenols, cobalt,manganese, titanium, zirconium, hafnium, vanadium or cerium salts and/orcomplexes in which the metals mentioned may have one of the oxidationnumbers II, III, IV, V or VI.

The detergents according to the invention may additionally enzymes, suchas proteases, amylases, pullulanases, cutinases and lipases, for exampleproteases, such as BLAP®, Optimase®, Opticlean®, Maxacal®, Maxapem®,Esperase® and/or Savinase®; amylases, such as Termamyl®, Amylase-LT®,Maxamyl®, Duramyl® and/or Purafect® OxAm; lipases, such as Lipolase®,Lipomax®, Lumafast® and/or Lipozym®. As described for example inInternational patent applications WO 92/11347 or WO 94/23005, theenzymes optionally used may be adsorbed onto supports and/orencapsulated in shell-forming substances to protect them againstpremature inactivation. They are present in the detergents according tothe invention in quantities of preferably not more than 2% by weightand, more preferably, between 0.1% by weight and 0.7% by weight.

If the detergents foam excessively in use, up to 6% by weight andpreferably about 0.5% by weight to 4% by weight of a foam-suppressingcompound, preferably from the group of silicone oils, mixtures ofsilicone oil and hydrophobicized silica, paraffins, paraffin/alcoholcombinations, hydrophobicized silica, bis-fatty acid amides and otherknown commercially available foam inhibitors may be added to them. Otheroptional ingredients in the formulations according to the invention are,for example, perfume oils.

Organic solvents suitable for use in the formulations according to theinvention, particularly where they are present in liquid or paste-likeform, include alcohols containing 1 to 4 carbon atoms, more particularlymethanol, ethanol, isopropanol and tert.butanol, diols containing 2 to 4carbon atoms, more particularly ethylene glycol and propylene glycol,and mixtures thereof and the ethers derived from compounds belonging tothe classes mentioned above. Water-miscible solvents such as these arepresent in the detergents according to the invention in quantities ofpreferably not more than 20% by weight and, more preferably, inquantities of 1% by weight to 15% by weight.

To establish a desired pH value which is not automatically adjusted bythe mixture of the other components, the formulations according to theinvention may contain system-compatible and ecologically compatibleacids, more particularly citric acid, acetic acid, tartaric acid, malicacid, lactic acid, glycolic acid, succinic acid, glutaric acid and/oradipic acid, and mineral acids, more particularly sulfuric acid oralkali metal hydrogen sulfates, or bases, more particularly ammonium oralkali metal hydroxides. pH regulators such as these are present in theformulations according to the invention in quantities of preferably notmore than 10% by weight and, more preferably, between 0.5% by weight and6% by weight.

In one preferred embodiment, machine dishwashing detergents according tothe invention contain 50% by weight to 60% by weight of sodiumphosphate, 15% by weight to 25% by weight of sodium carbonate or amixture thereof with polymeric polycarboxylate, 5% by weight to 15% byweight of sodium perborate or percarbonate, 0.5% by weight to 5% byweight of bleach activator eliminating peroxocarboxylic acid underperhydrolysis conditions, 0.5% by weight to 7.5% by weight ofsurfactant, 2% by weight to 10% by weight of sodium silicate and 0.1% byweight to 0.75% by weight of silver corrosion inhibitor, moreparticularly benzotriazole.

The production of solid formulations according to the invention does notinvolve any difficulties and may be carried out by methods known inprinciple, for example by spray drying or granulation, the peroxygencompound and bleach catalyst optionally being separately added later.

Detergents according to the invention in the form of aqueous solutionsor solutions containing other typical solvents are produced withparticular advantage simply by mixing the ingredients which may beintroduced into an automatic mixer either as such or in the form of asolution.

The detergents according to the invention are preferably present aspowders, granules or tablets which may be produced in known manner, forexample by mixing, granulation, roll compacting and/or by spray dryingof the heat-resistant components and adding the more sensitivecomponents, including in particular enzymes, bleaching agents and thebleach catalyst.

Detergents according to the invention in tablet form are preferablyproduced by mixing all the ingredients in a mixer and tableting theresulting mixture in conventional tablet presses, for example eccentricpresses and rotary presses, under pressures of 200·10⁵ Pa to 1,500·10⁵Pa. Fracture-resistant tablets dissolving sufficiently quickly underin-use conditions with flexural strengths of normally >150 N are readilyobtained in this way. A tablet thus produced has a weight of 15 to 40 gand preferably 20 g to 30 g for a diameter of 35 mm to 40 mm.

Detergents according to the invention in the form of dust-free, storablefree-flowing powders or granules with high bulk densities of 800 to1,000 g/l can be produced by first mixing the builder components with atleast part of the liquid components to increase the bulk density of thisso-called compound and then combining the other ingredients of theformulation, including the bleach catalyst, with the resulting compound,if desired after drying.

Machine dishwashing detergents according to the invention may be usedboth in domestic dishwashing machines and in institutional dishwashingmachines. They are added by hand or by suitable dispensers. The in-useconcentrations in the wash liquor are generally about 1 to 8 g/l andpreferably 2 to 5 g/l.

A machine wash program is generally augmented and terminated by a fewrinse cycles with clear water following the main wash cycle and a finalrinse cycle with a conventional rinse aid. After drying, completelyclean and hygienically satisfactory dishes are obtained using adetergent according to the invention.

EXAMPLES

A machine dishwashing detergent (C1) containing 45 parts by weight ofsodium citrate, 5 parts by weight of sodium carbonate, 31 parts byweight of sodium hydrogen carbonate, 1 part by weight of proteasegranules and 1 part by weight of amylase granules, 2 parts by weight ofnonionic surfactant and also 12 parts by weight of sodium percarbonateand 2 parts by weight of N,N,N′,N′-tetraacetylethylenediamine (TAED), adetergent (C2) containing 10 parts by weight of sodium percarbonate and4 parts by weight of TAED for otherwise the same composition as V1, adetergent according to the invention (M1) containing 0.025 part byweight of nitropentammine cobalt(III) chloride for otherwise the samecomposition as V1 and detergents according to the invention containing0.017 part by weight of tetrammine carbonato-cobalt(III) hydrogencarbonate monohydrate (M2), 0.016 part by weight of tetramminecarbonato-cobalt(III) nitrate hemihydrate (M3), 0.022 part by weight oftetrammine carbonato-cobalt(III) chloride (M4) or 0.034 part by weightof pentammine nitrato-cobalt(III) perchlorate (M5) for otherwise thesame composition as V2 were tested as described in the following:

To produce standardized tea films, teacups were immersed 25 times in atea solution heated to 70° C. A little of the tea solution was thenpoured into each teacup after which the teacups were dried in a dryingcabinet. 8 of the tea-stained teacups were then washed in a Bosch® G 575dishwasher (20 g detergent, 55° C. program, water hardness 14° dH to 16°dH) after which film removal was visually scored on a scale of 0(=unchanged very pronounced film) to 10 (=no film).

TABLE 3 Film Removal Scores Detergent Score M1 7 M2 9 M3 9-10 M4 9 M5 9C1 3 C2 4

It can be seen that a far better bleaching effect can be obtained by theuse according to the invention (M1 to M5) than by the conventionalbleach activator TAED alone (C1 or C2). Substantially the same or evenslightly better results were obtained when the sodium percarbonate inthe detergents according to the invention was replaced by sodiumperborate.

What is claimed is:
 1. A method of cleaning a hard surface comprisingthe steps of activating a peroxygen compound with a complex of formulaI: [M_(n)(NH₃)_(6−x)(L)_(x)]A_(n)  (I) wherein M is a transition metalselected from the group consisting of iron, copper, and ruthenium, L isa ligand selected from the group consisting of water, hydroxide,chlorate, perchlorate, (NO₂)⁻, carbonate, nitrate, halide, andthiocyanate, x is a number of 0 to 5, A is a salt-forming anion, n is anumber such that the complex of formula (I) has no charge, andcontacting a hard surface with an effective amount of an aqueouscleaning solution comprising the activated peroxygen compound.
 2. Amethod according to claim 1, wherein the peroxygen compound isinorganic.
 3. A method of cleaning a hard surface comprising the stepsof activating a peroxygen compound with a bridged binuclear complex of atransition metal selected from the group consisting of cobalt, iron,copper, and ruthenium, said complex containing at least 1 ammonia ligandper transition metal atom, and contacting a hard surface with aneffective amount of an aqueous cleaning solution comprising theactivated peroxygen compound, wherein the complex has a bridge ligandselected from the group consisting of oxo, hydroxo, peroxo, amido,imido, and imino.
 4. A method according to claim 3, wherein the complexhas at least 4 ammonia ligands per transition metal atom.
 5. A methodaccording to claim 1, wherein the transition metal is iron.
 6. A methodaccording to claim 3, wherein the transition metal is cobalt.
 7. Amethod according to claim 1, wherein the transition metal has anoxidation number of +3.
 8. A method according to claim 3, wherein thetransition metal has an oxidation number of +3.
 9. A method according toclaim 1, wherein L is a halide or an (NO₂)⁻ group.
 10. A methodaccording to claim 1, wherein A is selected from the group consisting ofnitrate, hydroxide, hexafluorophosphate, sulfate, chlorate, perchlorate,halide, and an anion of a carboxylic acid.
 11. A method according toclaim 10, wherein the anion of a carboxylic acid is selected from thegroup consisting of formate, acetate, benzoate, and citrate.
 12. Amethod according to claim 1, wherein the peroxygen compound is selectedfrom the group consisting of organic per acids, hydrogen peroxide,perborate, percarbonate, and mixtures thereof.
 13. A dishwashingdetergent composition comprising 0.0025% to 0.25% by weight of a bleachcatalyst comprising a complex of a transition metal selected from thegroup consisting of iron, copper, and ruthenium, said complex containingat least 1 ammonia ligand, 50% to 60% by weight of sodium phosphate, 15%to 25% by weight of sodium carbonate or a mixture thereof with polymericpolycarboxylate, 5% to 15% by weight of sodium perborate orpercarbonate, 0.5% to 5% by weight of a bleach activator that eliminatesperoxocarboxylic acid under perhydrolysis conditions, 0.5% to 7.5% byweight of a surfactant, 2% to 10% by weight of sodium silicate, and 0.1%to 0.75% by weight of a silver corrosion inhibitor.
 14. A dishwashingdetergent according to claim 13 comprising 0.01% to 0.1% by weight ofthe bleach catalyst.
 15. A dishwashing detergent according to claim 13wherein the complex contains at least 5 ammonia ligands.
 16. A detergentaccording to claim 13, wherein the silver corrosion inhibitor isbenzotriazole.